The First Step in Vision: Femtosecond Isomerization of Rhodopsin

Schoenlein, R. W.; Peteanu, Linda A.; Mathies, R. A.; Shank, C. V.

doi:10.1126/science.1925597

Cited by 854 publications

(874 citation statements)

References 21 publications

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“…Finally, we compare our spectral results to the difference of two L-edge spectra of the crystalline spin cross-over compound Fe II (phen) 2 (NCS) 2 , plotted in Figure 4B (grey line). The difference spectrum is derived from static measurements of the low-spin and high-spin L 2,3 -edges by Briois and coworkers.…”

Section: Resultsmentioning

confidence: 99%

Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

et al. 2010

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Solution-phase photo-induced low-spin to high-spin conversion in the Fe II polypyridyl complex [Fe(tren(py) 3 )] 2+ (where tren(py) 3 is tris(2-pyridylmethylimino-ethyl)amine) has been studied via picosecond soft x-ray spectroscopy. Following 1 A 1 → 1 MLCT (metal-to-ligand charge transfer) excitation at 560 nm, changes in the iron L 2 and L 3 edges were observed concomitant with formation of the transient high-spin 5 T 2 state. Charge-transfer multiplet calculations coupled with data acquired on low-spin and high-spin model complexes revealed a reduction in ligand field splitting of ~1 eV in the high-spin state relative to the singlet ground state. A significant reduction in orbital overlap between the central Fe-3d and the ligand N-2p orbitals was directly observed, consistent with the expected ca. 0.2 Å increase in Fe-N bond length upon formation of the high-spin state. The overall occupancy of the Fe 3d-orbitals remains constant upon spin-crossover, suggesting that the reduction in σ-donation is compensated by significant attenuation of π-back-bonding in the metal-ligand interactions. These results demonstrate the feasibility and unique potential of time-resolved soft x-ray absorption spectroscopy to study ultrafast reactions in the liquid phase by directly probing the valence orbitals of first-row metals as well as lighter elements during the course of photochemical transformations.

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Section: Resultsmentioning

confidence: 99%

Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

et al. 2010

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“…It is a Z/E photo-switch, bearing a record isomerisation speed of 200 fs 2 and quantum yield of more than 60% 25 . Quantitative computations of the excited state of PSBR in rhodopsin 21 have triggered the design of a new family of photoswitches, the N-alkylated indanylidene pyrroline Schiff bases (NAIP) 26 , which mimic the photo-induced charge translocation and structural dynamics of the natural pigment.…”

Section: Photoisomerization Is Currently Described As a Process Involmentioning

confidence: 99%

Coherent ultrafast torsional motion and isomerization of a biomimetic dipolar photoswitch

Briand

Bräm

Réhault

et al. 2010

Phys. Chem. Chem. Phys.

103

163

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(<250 words). Femtosecond fluorescence up-conversion, UV-Vis and IRtransient absorption spectroscopy are used to study the photo-isomerization dynamics of a new type of zwitterionic photoswitch based on a N-alkylated idanylidene pyrroline Schiff base framework (ZW-NAIP). The system is biomimetic, as it mimics the photophysics of retinal, in coupling excited state charge translocation and isomerisation. While the fluorescence lifetime is 140 fs, excited state absorption persists over 230 fs in form of a vibrational wavepacket according to twisting of the isomerising double bond. After a short "dark" time window in the UV-visible spectra, which we associate to the passage through a conical intersection (CI), the wavepacket appears on the ground state potential energy surface, as evidenced by the transient mid-IR data. This allows for a precise timing of the photoreaction all the way from the initial Franck-Condon region, through the CI and into both ground state isomers, until incoherent vibrational relaxation dominates the dynamics. The photo-reaction dynamics remarkably follow those observed for retinal in rhodopsin, with the additional benefit that in ZW-NAIP the conformational change reverses the zwitterion dipole moment direction. Last, the pronounced low-frequency coherences make these molecules ideal systems for 3 investigating wavepacket dynamics in the vicinity of a CI and for coherent control experiments.4

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“…Similar low-frequency phonons contribute to the observed dynamics of retinal proteins involved in vision [20,21]. There, the importance of vibronic coupling follows intuitively from the structural change experienced by the chromophores, implicating a number of highly delocalized skeletal modes needed for isomerization.…”

Section: Introductionmentioning

confidence: 99%

Laser-Limited Signatures of Quantum Coherence

et al. 2015

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The observation of persistent oscillatory signals in multidimensional spectra of proteinpigment complexes has spurred a debate on the role of coherence-assisted electronic energy transfer as a key operating principle in photosynthesis. Vibronic coupling has recently been proposed as an explanation for the long lifetime of the observed spectral beatings. However, photosynthetic systems are inherently complicated, and tractable studies on simple molecular compounds are in demand to fully understand the underlying physics. In this work, we present measurements and calculations on a solvated molecular homodimer with clearly resolvable oscillations in the corresponding twodimensional spectra. Through analysis of the various contributions to the nonlinear response, we succeed in isolating the signal due to inter-exciton coherence. We find that while calculations predict a prolongation of this coherence due to vibronic coupling, the combination of dynamic disorder and vibrational relaxation leads to a coherence decay on a timescale comparable to the electronic dephasing time.

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The First Step in Vision: Femtosecond Isomerization of Rhodopsin

Cited by 854 publications

References 21 publications

Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

Coherent ultrafast torsional motion and isomerization of a biomimetic dipolar photoswitch

Laser-Limited Signatures of Quantum Coherence

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